The theory of Yin-Yang and Five Elements, which originated in the Yin and Zhou Dynasties, is still an important theory about the origin of the universe in this period. The theory of five elements evolved from the "five materials" of the Western Zhou Dynasty. In the Biography of Shangshu written by Fu Sheng in the early Han Dynasty, it was recorded that the king of Wu cut down the commercial suburbs, and the foot soldiers sang and danced, saying, "Those who are in fire and water, the people take food as the sky; Jin Mu, what the people are doing; The earth is the source of all things and is for human use. "Water, fire, gold, wood and soil are the five basic substances on which human beings live. This view has a long history. According to "Mandarin Zheng Yu", in the ninth year of Zhou Youwang (773 BC), Tashi said in response to Zheng Huangong's question, "So the former king and Jin Mu were mixed in fire and water, and they took Pepsi". This answer shows that at that time, soil and Jin Mu fire and water were only the basic substances of "all things" and did not rise to the origin of all things in the universe. There is a record about Liu Xiahui (Zhan Qin, who lived in the second half of the 7th century BC) in Zuo Zhuan: "He reached the five elements of the earth, so he was born again." This is the earliest word "five elements". In 572 BC, a passage recorded in Guoyu Zhou said: "There are six places in the sky and five places in the earth, and the number is constant. "Six Days" refers to Yin, Yang, Wind, Rain, Yin and Ming "Six Qi" and "Wu Di" refers to the five elements. It has certain philosophical significance to raise them to normal natural laws ("the regularity of numbers"). By the end of the 6th century BC, the five elements had expanded to all aspects (five flavors, five colors and five tones). ), and is regarded as one of the basic principles on which "ceremony" depends. In the book Shang Shu Hong Fan, which may be a fake of the Warring States period, it is further summarized as: "Five elements, one is water, the other is fire, the third is wood, the fourth is gold, and the fifth is earth. Moisturizing, fire inflammation, straight wood, golden leather, soil fertilizer. "Moistening the bottom makes it salty, burning the top makes it bitter, straight up makes it sour, leather makes it pungent and grains make it sweet." Here, the five elements are promoted to five basic elements that constitute everything in the universe, and their properties and functions are defined.
At the end of the Western Zhou Dynasty, there was also a saying that matter was "qi", which explained various natural phenomena such as the separation of heaven and earth, the change of seasons, the rise and fall of everything with the interaction of yin and yang. The weather is fine and nature is rising; Ground qi is yin, and its nature is stagnation. The coordination and resonance of the two kinds of qi produced the order of everything and heaven and earth; The disharmony between these two gases leads to catastrophic changes in nature. In the second year of Zhou Youwang (780 BC), an earthquake occurred in Sanchuan (now central Shaanxi) in the Western Zhou Dynasty. Dr. Zhou Boyang's father said that this was because "the yang lost its position and the town yin was depressed" and "the yang fell but could not go out, and the yin was forced but could not (rise)", so the earthquake occurred.